Evidence Based Medicine

Evidence Based Medicine: What is it? Third-year Family Practice Clerkship Orientation 2003-2004Jennifer M Joyce, MD

GoalsIntroduce evidence based medicine (EBM)Discuss the different types of information resources and information mastery skillsIntroduce the EBM assignment

Definitions Medicine:The art and science of the diagnosis, treatment, and prevention of disease and the maintenance of good health. EvidenceA thing or things helpful in forming a conclusion or judgment.

Definitions 2Evidenced-Based Medicine: Evidence-Based Medicine (EBM) is the integration of the best research evidence with clinical expertise and patient values.Sackett

The Art of IntegrationClinical EvidenceResearchEvidencePatientPreferences

Why EBM?Daily need for informationInadequacy of traditional sources of informationDisparity between our diagnostic skills and clinical judgment vs. up-to-date knowledge and clinical performanceDevelop skills for life long learning

Limitations of EBMLack of evidenceFunding sources limit the type and scope of research projectsAccess to information sources limited in clinical settingInadequate research models to assess for the complexity inherent in living systems.Lack of skills to use available information sources

INFORMATION MASTERYUsefulness of medical informationRelevance x Validitywork=Creating a culture of inquiry

Types of Information DatabasesPrimary sourcesPubMed, MedLineRequire more work to validateSecondary sourcesCochrane, Best Evidence, InfoPoemsAlready reviewed- less work to validateLimited amount of information studied

How good is the evidence? Is it from a peer-reviewed journal? (New England Journal of Medicine vs. Practice)Are the location and patients similar to mine?Sponsored by an organization that may influence the study design or results? Will the information, if true, have an impact on my patients and practice?

POEMs vs. DOEs P- PatientO- OrientedE Evidence thatM- MattersD- DiseaseO- OrientedE- Evidence

POEMs vs. DOEs

Example

Disease-Oriented Evidence

Patient-Oriented Evidence that Matters

Comment

Antiarrhythmic Therapy

Drug X ( PVCs on ECG

Drug X increases mortality

POEM study contradicts DOE study

Antihypertensive therapy

Antihypertensive therapy ( BP

Antihypertensive therapy ( mortality

POEM agrees with DOE

Prostate

Screening

PSA screening detects prostate cancer early

? whether PSA screening ( mortality

DOE exists, but the important POEM is unknown

AssignmentCompose a focused clinical questionConduct a search for the evidenceAppraise the evidence for relevanceAppraise the validity of the informationApply the information to patient care

Formulate a focused clinical questionP- PatientI- InterventionC- ComparisonO- Outcome

Conduct a Search for the EvidenceSearch secondary (pre-appraised) information sourcesCochraneBest EvidenceNational Guideline ClearinghouseSearch primary data sources

Appraise the evidence you findValidity screening-From a peer reviewed journal?-Location and patients similar to mine?-Sponsored by an organization that may influence the study design?-Will the information,if true, have an impact on my patients and practice?

Appraise the evidence Determine the intent of the articleTherapyDiagnosis and screeningCausationPrognosisEducation

Appraise the evidenceFun with NumbersRemember the important statistical values:Relative Risk ReductionAbsolute Risk ReductionNumber Needed to Treat (NNT)Sensitivity and SpecificityPositive and Negative Predictive ValuesLikelihood Odds RatiosMedical Center Library WebographiesCentre for Evidence Based Medicine

Apply the evidenceShort presentation at student conferenceConsider a short presentation to your preceptorContinue using evidence to support your common medical practices

Evaluate your performanceSelf evaluation is key to successfully practicing EBMAm I asking answerable clinical questions?Am I searching the literature?Are you becoming more efficient in your searches?Are you integrating your critical appraisals into your practice at all?

SummaryEvidence-based medicine is a systematic approach to use up to date information in the practice of medicineSkills are needed to integrate the available evidence with clinical experience and patient concernsApplication and evaluation of EBM skills will provide a frame work for life-long learning.

****by best research evidence we mean clinically relevant research, often from the basic sciences of medicine, but especially from patient centered clinical research into the accuracy and precision of diagnostic tests (including the clinical examination), the power of prognostic markers, and the efficacy and safety of therapeutic, rehabilitative, and preventive regimens. New evidence from clinical research both invalidates previously accepted diagnostic tests and treatments and replaces them with new ones that are more powerful, more accurate, more efficacious, and safer. by clinical expertise we mean the ability to use our clinical skills and past experience to rapidly identify each patient's unique health state and diagnosis, their individual risks and benefits of potential interventions, and their personal values and expectations. by patient values we mean the unique preferences, concerns and expectations each patient brings to a clinical encounter and which must be integrated into clinical decisions if they are to serve the patient. *An example, a 55 year old female is on Coumadin for heart valve replacement. The evidence suggests that she should be titrated to an INR of 2.5 to 3.5, yet she experienced a significant bleed when her INR was 3.8. The clinical experience for this patient suggest that an INR higher than 3.0 might be problematic for this patient. Her preference is to limit her INR as she fears another incidence of bleeding. Her your clinical experience with this patient and her wishes weigh against the standard clinical evidence.*our daily need for valid information about diagnosis, prognosis, therapy and prevention (up to 5 times per in-patientii and twice for every 3 out-patientsiii). the inadequacy of traditional sources for this information because they are out-of-date (textbooksiv), frequently wrong (expertsv), ineffective (didactic continuing medical educationvi) or too overwhelming in their volume and too variable in their validity for practical clinical use (medical journalsvii). the disparity between our diagnostic skills and clinical judgement, which increase with experience, and our up-to-date knowledgeviii and clinical performanceix, which decline. our inability to afford more than a few seconds per patient for finding and assimilating this evidencex, or to set aside more than half an hour per week for general reading and studyxi the development of strategies for efficiently tracking down and appraising evidence (for its validity and relevance)xii. the creation of systematic reviews and concise summaries of the effects of health care (epitomized by the Cochrane Collaborationxiii). the creation of evidence-based journals of secondary publication (that publish the 2% of clinical articles that are both valid and of immediate clinical usexiv). the creation of information systems for bringing the foregoing to us in seconds. the identification and application of effective strategies for life-long learning and for improving our clinical performancexv.

********P-Who am I interested in?I- What is the intervention?C- How is the intervention being compared?O- What are the outcomes of the intervention?*******